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Finding the Fourth Proportional to 427.98, 642.02 and 139.46

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Solution

The fourth proportional to 427.98, 642.02 and 139.46 is: 209.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.98 : 642.02 = 139.46 : x
  2. Step 2: Convert to fraction form
    427.98/642.02 = 139.46/x
  3. Step 3: Cross multiply
    427.98x = 642.02 × 139.46
  4. Step 4: Simplify right side
    427.98x = 89,536.11
  5. Step 5: Solve for x
    x = 89,536.11/427.98
  6. Step 6: Final answer
    x = 209.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.